Changed preferred backend to Memcached::Client

There were some weird problems with Cache::Memcached under load.
...
Preparing for adding render cache
Ability to use cache without a set current project
Maximum element size configuration
Parsed templates cache reimplemented

Cache now contains not just 'path' based info, but 'template' info too.
Plus ability to plug in different cache implementations as needed.
Interface for peeking at PageSupport buffer

+ a fix for old potential memory leak in reset()
Prepared for caching and benchmarking

Passes tests.
Benchmarking implemented
Benchmarking and caching
Support for 'auto_after'